Survival characteristics of periodontally-involved teeth: a 40-year study.

Four hundred and fifty-five teeth that were judged clinically to have a questionable prognosis were observed over a 40-year span in 166 patients in a private practice. Therapy initially was debridement with oral hygiene instruction, followed by flap curettage procedures and preventive maintenance recall therapy. An assessment of compliance based on oral hygiene and recall attendance was also performed. A total of 55 (12%) teeth were lost with an average survival rate of 8.8 years prior to extraction. No teeth were lost during the first 2 years of observation. The majority of extracted teeth were maxillary second molars (38.2%), followed by maxillary first molars (25.5%), and mandibular second molars (16.4%). Tooth loss patterns appeared to be bilaterally symmetrical, with 51% of teeth lost in the right quadrants and 49% lost in the left quadrants. Indications for extraction were primarily periodontal abscesses. Teeth that were considered to have a very questionable prognosis have been retained for many years after therapy, supportive treatment, and patient compliance with recall attendance.